Plamenatz, John
National News-Letter, 1949
Buku Teks
International Publ., 1970
Buku Teks
Fromm, Erich, author
IRCiSoD, 2020
Buku Teks
edited by Saxe Commins and Robert N. Linscott
Modern Pocket Library, 1947
Buku Teks
Derek Chadee
Wiley-Blackwell, 2011
Buku Teks